Authentication stream version check exists in 5.x only

Original comment by @tvernum:

In LINK REDACTED a LINK REDACTED was added to Authentication to ensure that the version of the serialized authentication matches the version of the connection it's being read from.

This check is in 5.x but is not in 6.x or master.

It's being triggered in LINK REDACTED due to what seems to be a real versioning issue in CCS, but the problem the customer is seeing doesn't occur in 6.x because the check isn't there (the version mismatch exists, it just doesn't throw any exceptions)

Do we want to add that check in to 6.x and 7.x ?